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diff --git a/sphinx/parsers.py b/sphinx/parsers.py
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+"""A Base class for additional parsers."""
+
+from __future__ import annotations
+
+from typing import TYPE_CHECKING, Any
+
+import docutils.parsers
+import docutils.parsers.rst
+from docutils import nodes
+from docutils.parsers.rst import states
+from docutils.statemachine import StringList
+from docutils.transforms.universal import SmartQuotes
+
+from sphinx.util.rst import append_epilog, prepend_prolog
+
+if TYPE_CHECKING:
+    from docutils.transforms import Transform
+
+    from sphinx.application import Sphinx
+    from sphinx.config import Config
+    from sphinx.environment import BuildEnvironment
+
+
+class Parser(docutils.parsers.Parser):
+    """
+    A base class of source parsers.  The additional parsers should inherit this class instead
+    of ``docutils.parsers.Parser``.  Compared with ``docutils.parsers.Parser``, this class
+    improves accessibility to Sphinx APIs.
+
+    The subclasses can access sphinx core runtime objects (app, config and env).
+    """
+
+    #: The config object
+    config: Config
+
+    #: The environment object
+    env: BuildEnvironment
+
+    def set_application(self, app: Sphinx) -> None:
+        """set_application will be called from Sphinx to set app and other instance variables
+
+        :param sphinx.application.Sphinx app: Sphinx application object
+        """
+        self._app = app
+        self.config = app.config
+        self.env = app.env
+
+
+class RSTParser(docutils.parsers.rst.Parser, Parser):
+    """A reST parser for Sphinx."""
+
+    def get_transforms(self) -> list[type[Transform]]:
+        """
+        Sphinx's reST parser replaces a transform class for smart-quotes by its own
+
+        refs: sphinx.io.SphinxStandaloneReader
+        """
+        transforms = super().get_transforms()
+        transforms.remove(SmartQuotes)
+        return transforms
+
+    def parse(self, inputstring: str | StringList, document: nodes.document) -> None:
+        """Parse text and generate a document tree."""
+        self.setup_parse(inputstring, document)  # type: ignore[arg-type]
+        self.statemachine = states.RSTStateMachine(
+            state_classes=self.state_classes,
+            initial_state=self.initial_state,
+            debug=document.reporter.debug_flag)
+
+        # preprocess inputstring
+        if isinstance(inputstring, str):
+            lines = docutils.statemachine.string2lines(
+                inputstring, tab_width=document.settings.tab_width,
+                convert_whitespace=True)
+
+            inputlines = StringList(lines, document.current_source)
+        else:
+            inputlines = inputstring
+
+        self.decorate(inputlines)
+        self.statemachine.run(inputlines, document, inliner=self.inliner)
+        self.finish_parse()
+
+    def decorate(self, content: StringList) -> None:
+        """Preprocess reST content before parsing."""
+        prepend_prolog(content, self.config.rst_prolog)
+        append_epilog(content, self.config.rst_epilog)
+
+
+def setup(app: Sphinx) -> dict[str, Any]:
+    app.add_source_parser(RSTParser)
+
+    return {
+        'version': 'builtin',
+        'parallel_read_safe': True,
+        'parallel_write_safe': True,
+    }